This project continues to provide high quality clinical diagnostic microbiology to discover bacteria, mycoplasma, and fungi which cause infection in cancer patients. In addition, the presence of viruses are investigated and rises in viral serum antibodies are determined. Initial surveillance cultures determine the patients' flora upon admission to the hospital, and acquisition of potentially pathogenic organisms during the hospital stay is determined by surveillance cultures from high risk patients that are repeated on a routine basis. Cultures of the environment enable the evaluation of cleaning procedures, the detection of "shedders" of pathogenic organisms, and also provide data on the efficacy of protective environments. A total of 25,952 patient and environmental samples were cultured during the 12-month period of 4/1/76-3/31-77. Serotyping or bacteriophage typing were performed on all strains of Pseudomonas aeruginosa, Serratia marcescens, and Staphylococcus aureus in order to evaluate the epidemiology of these species in cancer patients and their role in possible cross infections. New antibiotics were tested for in vitro minimum inhibitory concentrations, and development of resistance was monitored. A serum bank provides a collection of sera from cancer patients for research purposes.